address issues raised in @bnoordhuis's review: - eliminate redundant resetting of `Persistent` members in destructor - save the context (ie realm) at the time the task is created - create an `Isolate::Scope` and `Context::Scope` on the stack before calling the callback - scope the `TryCatch` so it clears the pending exception before calling the callback
address issues raised in @bnoordhuis's review:
- eliminate redundant resetting of `Persistent` members in destructor
- save the context (ie realm) at the time the task is created
- create an `Isolate::Scope` and `Context::Scope` on the stack before calling the callback
- scope the `TryCatch` so it clears the pending exception before calling the callback

dherman/nanny,rustbridge/neon,rustbridge/neon,neon-bindings/neon,dherman/nanny,neon-bindings/neon,neon-bindings/neon,dherman/nanny,rustbridge/neon,dherman/nanny,rustbridge/neon,rustbridge/neon,rustbridge/neon,neon-bindings/neon